Apparatus and method for acquiring and reading optical codes with result indication

ABSTRACT

In an apparatus and a method for acquiring and reading optical codes, the indication of the reading result is carried out projecting a luminous figure onto the optical code, that is to say in the position on which the attention of the operator is focused. The luminous figure can have an information content also more complex than the simple indication of the end of the reading.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and a method for acquiringand reading optical codes, with indication of the result of the readingitself.

2. Description of the Prior Art

In this description and the following claims, by the expression “opticalcode”, bar codes, stacked codes, that is, with a plurality of stackedbar sequences, bidimensional codes, colour codes, and the like should bemeant.

Moreover, by “acquisition of an optical code”, the whole of illumination(or scan) of the code with a light beam, detection of the light diffusedby the code, and its transformation into electric signal is meant, whileby “reading of an optical code”, the processing of the electric signaland its interpretation or decoding are meant.

Finally, by “indication of the reading result”, also the mere indicationof the end of the reading, or of the unsuccessful reading attempt, ismeant.

Known optical code acquisition and reading apparatuses, or briefly,readers, are essentially provided with a light source for generating alight beam which is projected onto the optical code to be read, forexample through slits and lenses, herein in general referred to with theexpression “illumination optics”, optical elements suitable to collectand focus the light diffused by the code, for example slits and lenses(in general referred to with the expression “receiving optics”),photosensitive elements on which the light collected by the receivingoptics is focused, suitable to detect the light diffused by the code andto convert it into an electric signal reproducing as much accurately aspossible the reflectance modulations of the elements making up the code,as well as processing means for interpreting or decoding the code so asto obtain the significant information contained in it, such as forexample manufacturer, name of the specific product, production lot,price, etcetera.

The operation of reading a particular optical code can give negativeresults for various factors, among which the imperfection of the codedue, for example, to damages to the label on which it is obtained, thedistance between the reader and the code, or the maintenance of saiddistance during the scanning time. In addition, also when the code iscorrectly acquired, its decoding may be impossible because, for example,it does not fall within the categories of codes known by the reader. Inany case, the operator needs to know whether the code has been decodedbefore proceeding to read another code.

These problems are especially severe in the case of the so-called manualor hand-held readers, of the gun type.

Thus, in optical-code readers, simple indication devices are known andcurrently used for indicating to the user that the particular aimedoptical code has been decoded by the reader.

Said indication is normally generated using a light source made up ofone or more light emitting diodes (LEDs) arranged in the reader body, inthe proximity of the outer surface or inside it. Since in both cases theLED must be visible from the outside, the light emitted by the LED canbe refracted and/or diffused so as to be more visible towards theoperator. However, the image of the reader body usually is at the edgesof the operator's field of view, whose look is focused on the opticalcode. This is particularly true for codes of small sizes, or for stackedcodes, whose reading requires a precise movement of the hand. Thus, theperception of the lighting of the LED arranged into the reader body maynot be immediate.

To improve the perception of the indication that the reading hasoccurred, also when the visual attention of the operator is not focusedon the reader, the lighting of the LED is commonly accompanied by anacoustic signal, provided for example by an electromagnetic acoustichorn, commonly called buzzer, or beeper. However, also this provision isnot totally satisfactory since the acoustic signal cannot be easilyheard if the operation is carried out in a noisy environment or by anoperator with auditory deficiency. Moreover, a frequently repeatedacoustic signal may be annoying for the operator who must carry out veryfrequent readings and/or for a long time interval.

The European patent application N. 98830656.9 by the same Applicant,which represents a document of the prior art according to Art. 54 (3)EPC, describes an optical device comprising at least one illuminatingassembly active on a portion of the reading area along an emissionoptical path, wherein said at least one illuminating assembly comprises:a light source; a diaphragm having a predetermined shape for selecting aportion of the light generated by said source; and a converging lensarranged downstream of the diaphragm for collimating the shaped lightcoming from the diaphragm and projecting it onto the portion of readingarea.

However, said device is intended for the aiming and the visualindication of the area in which the optical code is, while the abovedocument does not provide for any indication on the use of such a devicefor indicating the result of the optical code reading.

SUMMARY OF THE INVENTION

The technical problem underlying the present invention is to provide anapparatus and a method for reading optical codes, which should becapable of providing an indication of the reading result immediatelyperceptible by the operator.

A more ambitious object of the present invention is to provide such anapparatus and method, wherein the indication of the reading resultshould be more significant, that is, with greater information content.

The Applicant has found that the aforesaid technical problem can besuccessfully overcome by projecting a luminous figure on the opticalcode being read, that is to say, in the position on which the operator'sattention is focused. Moreover, making use of this inventive idea, it ispossible to project, at the code, a wide range of useful information forthe operator, also more complex and o elaborate than the simpleindication of the end of decoding, thus satisfying also the aforesaidsecond object.

Thus, in a first aspect thereof, the present invention relates to anapparatus for acquiring and reading optical codes, comprising:

means for acquiring the optical code, having at least one acquisitionlight source,

means for reading the acquired optical code, and

means for visually indicating the reading result,

characterised in that said visual indication means comprises:

at least one indication light source, distinct from or coinciding with,the at least one acquisition light source of said acquisition means,

means for imposing an information content indicating the reading resultto the light emitted by said at least one indication light source, and

means for projecting the light, having the imposed information content,substantially at the optical code.

In this description and the following claims, by “substantially at theoptical code” it is meant on the surface bearing the optical code and inclose proximity or coincidence with the optical code itself.

Advantageously, the means for reading the optical code comprises meansfor communicating the acquired code to a remote processing unit and forreceiving the reading result therefrom.

In an embodiment, the means for imposing the information contentcomprises a switch for switching on and off the at least one indicationlight source. This embodiment has the advantage of being very simple.

In an alternative embodiment, the means for imposing the informationcontent comprises at least one element for selectively transmitting thelight generated by the at least one indication light source. With thisprovision, it is possible to generate luminous figures having suchshapes or hues as to be immediately recognisable by the operator asbeing different from the illumination line used for acquiring the code,by simply switching on and off the light source.

More in particular, the selective transmission element can be adiffractive element, a diaphragm having a predetermined shape, a slide,a reflecting surface having a predetermined shape and a shutter. Forexample, in the case of a diaphragm, the predetermined shape can consistin an elementary geometrical figure or it can have greater suggestivecontent. If the light source emits white light, it is also possible touse a colour slide. In the case of reflecting surface, the lighttransmitted to the projection means can alternatively be only thereflected light or only the light that is not back reflected.

As an alternative, the selective transmission element can be adiffractive element or a hologram. In this case, the information contentis imposed by modifying the wave front of the light beam. Thediffractive elements can be, for example, diffractive gratings, and theholograms can be, for example, Computer Generated Holograms.

In another embodiment, the means for imposing the information contentcomprises a driving circuit of the at least one light source. In fact,also by properly driving the light source, it is possible to obtainprojected images immediately recognisable by the operator as beingdifferent from the illumination line used for acquiring the code.

Preferably, the driving circuit is suitable to drive the at least oneindication light source also in such an operating condition that the atleast one indication light source is the acquisition light source duringthe acquisition of the optical code. By providing a shared light sourcefor both the acquisition of the optical code and the indication of thereading result, it is possible to maintain a small size of the apparatusand low costs.

Advantageously, the at least one indication light source is a lightsource capable of emitting light of at least two chromatic components,and the driving circuit is suitable to drive the at least one indicationlight source so as to generate each time light of one or more of saidchromatic components. In this way, the projected image has aninformation content coded by its colour. Moreover, one of the generatedhues can be that needed for acquiring the code.

As an alternative, the driving circuit is suitable to switch on the atleast one indication light source at least intermittently. Also withthis provision it is possible to generate projected imagesdifferentiated by intermittence times and distinguishable from the lightemitted by the acquisition source, which is typically continuous.Moreover, the light source can coincide with the acquisition source.Said light source typically is a plurality of LEDs or a laser beamwhich, for the acquisition of the code, is evenly scanned on the opticalcode, while for the indication of the reading result, it is madeintermittent or kept still so as to generate a fixed luminous point.

Alternatively, the driving circuit can be suitable to modulate theintensity of the at least one indication light source. Also in this way,it is possible to generate projected images differentiated from oneanother and with respect to the acquisition light, typically having evenand constant intensity, both with separate light sources and with thesame light sources used for the acquisition.

Typically, the means for projecting the light comprises at least oneconverging lens for collimating the light and focusing it substantiallyat the optical code.

Advantageously, the means for projecting the light is comprised of theillumination optics of the acquisition means. In this way, the apparatuscan keep a small size and low cost.

Analogously, the means for projecting the light can be comprised of thereceiving optics of the acquisition means.

Advantageously, the visual indication means also comprises second meansfor projecting the light emitted by the at least one light source or asecond light emitted by a second indication light source towards theoperator of the apparatus. Alternatively or in addition, the apparatuscan comprise acoustic indication means associated to the visualindication means. Retaining in this way also the traditional modalitiesof indication, in practice the apparatus is suitable for all operatingconditions.

In a second aspect thereof, the present invention relates to a methodfor acquiring and reading optical codes, comprising the steps ofacquiring and reading an optical code through an optical code acquiringand reading apparatus, and visually indicating the result of the readingstep, wherein the indication step is carried out by generating at leastone luminous figure substantially at the optical code.

Preferably, the method comprises the step of discriminating the resultof the reading step, and the indication step is carried out bygenerating a predetermined luminous figure associated to the particulardiscriminated result. By providing different indications associated tothe particular reading result, the operator is in any case provided withan indication.

Typically, the result discrimination step is carried out bydiscriminating between positive result and negative result.

Preferably, the result discrimination step is carried out bydiscriminating among positive result and at least two different negativeresults. In this way, the operator can recognise, for example, if thereading is impossible due to causes relating to the optical code or dueto a wrong operation of the reader, and he can thus implement, wherepossible, the necessary corrective measures, otherwise giving up furtherattempts.

Preferably, the indication step is carried out only after havingrepeated the reading step for a predetermined number of times receivinga negative result. In this way, temporary reading faults can beautomatically overcome.

Typically, the predetermined luminous figures generated in theindication step are differentiated by hue, shape and/or dynamics of theluminous intensity. In all these ways, or by properly combining them, itis possible to transmit also complex information contents to theoperator of the optical code reader.

Advantageously, the indication step is carried out by also generating atleast a second luminous information at the optical code acquiring andreading apparatus.

Moreover, preferably, the luminous information generated substantiallyat the optical code is turned off before turning off the second luminousinformation at the optical code reading apparatus. With this provision,it is possible to generate a short indication in the ideal location anda longer visual indication, even if not in the ideal location.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will now beillustrated with reference to some embodiments, depicted by way ofnot-limiting example in the attached drawings, wherein:

FIG. 1 shows a partial view of an apparatus for reading optical codeshaving indication means separate from the means for acquiring the code;

FIG. 2 schematically shows laser indication means for such an apparatus;

FIG. 3 shows a partial view of an apparatus for reading optical codeshaving indication means integrated with the means for acquiring thecode;

FIG. 4 shows a flow chart useful for describing the method according tothe invention; and

FIG. 5 shows another flow chart useful for describing the methodaccording to the invention.

DETAILED DISCUSSION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically shows a portion of an apparatus 10 for readingoptical codes incorporating a first embodiment of the present invention.The receiving portion of the optical code reader 10 is shown, comprisedof an objective 12 having a reception axis 14, and of a sensor 16, whilethe portion for illuminating the optical code is not illustrated.

In fact, this embodiment of the present invention provides for the useof a totally separate light source and optics for indicating the resultof an optical code reading, which indication occurs by projecting aluminous figure towards the surface bearing the optical code.

More in particular, the apparatus 10 shown in FIG. 1 comprisesindication means 20 in the form of a light source 22, a diaphragm 24substantially adjacent to the light source, and a lens 26, kept alignedalong an optical axis 28 by a support 30.

In the simplest embodiment, diaphragm 24 and lens 26 are not essential,as the mere switching on of LED 22 is sufficient for the luminousindication.

Light source 22 can be, for example, a light emitting diode (LED),preferably independently fed with respect to any other LEDs (or laserdiodes) used in the reader for illuminating the code. Light source 22must be sufficiently luminous for generating a luminous figure whichmust be clearly visible also in a well-lighted environment. LEDsavailable on the market that can be used as the light source 22 are, forexample, the LEDs model HLMP-CM15 supplied by Hewlett Packard, PaloAlto, Calif. (USA), with an epoxy resin package having a diameter of 5mm, peak wavelength (λ) of λ=524 nm and emission angle of 15°, or theLEDs model LT5413 by OSRAM, Munich, Germany, having a peak wavelengthλ=525 nm and package and emission angle equal to the LEDs of theprevious type. Both these LEDs emit a green light.

In fact, the light source 22 of the indication means 20 can emit lightof any colour, but green light is preferably used. In fact, green lightis universally used for giving positive indications or indications of agood operation, as for traffic lights or the indication LEDs onelectronic equipment, and in addition, the light of the illuminator foracquiring of the code is usually red; thus, green light allowshighlighting the difference with respect to the light projected forilluminating the optical code for its acquisition.

The optical code reader can be of the type comprising some LEDs and anillumination optics for illuminating the optical code, and a receivingoptics and a sensor of the charge coupled device (CCD) type, or of theComplementary Metal Oxide Semiconductor (C-MOS) type for receiving theluminous signal coming from the code and transforming it into anelectric signal. Moreover, both types of sensors can be of the linear orof the bidimensional type. The reader can also be of the type comprisinga laser diode, an illumination optics and scan means for generating ascan and thus, illuminating the optical code, and a receiving optics anda photodiode for receiving the luminous signal coming from the code, andtransforming it into an electric signal. In the continuation of thisdescription, the expressions “means (or light sources) for illuminatingthe optical code and/or for acquiring the optical code” will be usedwithout distinction for both types of optical code readers.

Moreover, both types of readers comprise means for processing theelectric signals and decoding the optical code read. The means forprocessing the electric signal and/or for decoding the code can becontained “on board” of the reader itself, or they can be “remote”. Thatis to say, through a cable or cordless connection the electric signalscan be sent to a processing unit far from the reader, which processingunit then communicates to the reader the occurrence or non-occurrence ofthe code decoding (or reading). In the continuation of this description,the processing of the electric signal and/or its decoding are referredto with the expression “code reading”.

As an alternative to monochromatic LEDs, which emit in a restricted bandof the visible spectrum, it is possible to use LEDs that emit asubstantially white light or other variants, which shall be furtherdescribed hereafter.

Diaphragm 24 is intended to block part of the light emitted by the lightsource 22. Said diaphragm can be of any shape, wherein its portiontransparent to the luminous radiation is made with the shape of thedesired luminous figure to be projected, as visual indication of thereading result, on the optical code or in its immediate proximity.

For example, diaphragm 24 can have a circular-shaped free aperture 25.Diaphragm 24 is advantageously arranged substantially in contact withLED 22 in order to allow a portion of light as wide as possible to passthrough the free aperture 25. Moreover, diaphragm 24 can be made as aseparate piece to be inserted into support 30, or it can be directlyobtained in the support 30.

As an alternative to the circular shape, the free aperture of diaphragm24 can have any other shape. For example, in terms of the immediacy ofthe result indication, it can be advantageous to use free apertures 25having a more significant shape, such as a checkmark (✓), a caption suchas “OK”, “READ” or the like, a more complex figure such as a closed handwith the thumb up, or the manufacturer's logo. On the contrary, if theresult indication represents the negative result of the reading, it canbe advantageous to use symbols such as an X or captions such as “NO”,“FAIL”, or the like, or a more complex figure such as a closed hand withthe thumb down.

In addition, it is possible to use more diaphragms at the same time,illuminated by the same source or by a respective source in order toobtain several spaced luminous figures, or a diaphragm 24 having morefree apertures 25. Moreover, it must be evident that in each case,diaphragm 24 or the like can be illuminated by more than one LED so asto increase the intensity of the luminous figure.

Diaphragm 24 must be considered as exemplary for means for imposing aninformation content to the projected light, i.e. for generating aparticular preselected figure. In this respect, diaphragm 24 providedwith the free aperture 25 allows obtaining a projected image having onlytwo luminosity levels (light and shadow). In order to obtain a scale ofintermediate luminosity levels between dark and light, it can beadvantageously replaced with a variable-transparency membrane or with aslide, which in the case of using a light source 22 emitting whitelight, can be a colour slide.

In a further alternative embodiment, the light beam emitted by source 22can be shaped by a reflecting surface substantially having the sameshape as the desired luminous figure to be used as a result indication,and being arranged so as to intercept part of the light of the lightsource 22 and send it towards lens 26. Manifestly, in this case thethree elements will not be aligned along the optical axis 28.Alternatively, the reflecting surface can be used for transmitting thenon-reflected light as indication figure complementary to its shape. Inthis case, the back-reflected light can for example be used as thesource of the traditional indication means, which emits at the body ofthe reading apparatus.

Advantageously, apparatus LO can comprise more than one indicationsystem 20 such as that exemplified, each used for a differentindication. For example, besides indicating the successful reading, itis possible to indicate that the decoding of the optical code was notpossible within a maximum time or a maximum number of attempts. In thiscase, for example, a red luminous figure shall be used, for example anX. More advantageously, the negative result of the decoding can bediscriminated from a series of typologies, for example because the codeis damaged, or because in the specific operating conditions, the readeris not capable of carrying out the decoding, or because the code readdoes not fall within the categories known by reader 10. The generatedindication figure will be differentiated in various ways, for example byits colour and/or shape.

In an equivalent way, it is possible to use indication means allowingthe projection of a variable luminous figure so as to provide moreinformation to the operator of apparatus 10. For example, also inabsence of diaphragm, the light source 22 can be made up of any set oftwo or more LEDs with a predetermined geometrical arrangement, of aback-lighted Liquid Crystal Display (LCD), of a segment LED matrix asalphanumeric displays (for example, that commercially available asSA05-11SRWA from Kingbright, Taiwan, comprised of seven-segment LEDs,having wavelength λ=660 nm, and representing characters with a height of12.7 mm), of a dot LED matrix (for example, that commercially availableas TA07-11SRWA from Kingbright, formed of 5×7 dots, having dimensions of12.7×18 mm², and emitting light with peak wavelength λ=660 nm). Saidalphanumerical result indication can be used for indicating an errormessage explaining the reason why the code is not read. In the case ofpositive result of the decoding of the optical code, the same indicationcan at the same time provide information relating to the content of theoptical code read, or to part of it, for example the product or themanufacturer's name, or a category among a series of preselectedcategories. For example, each product can be associated to the placewhere it is to be stored, possible discounts applied to the product,etcetera.

Alternatively, as light source it is possible to use multi-chip LEDscontaining two or more chips, with different emission bands, and whichcan be turned on independently, such as for example the red and greendual-chip LED LU 5351-JM commercially available from OSRAM, or RGB LEDssuch as the LEDs KAA-3528EMBSGC from Kingbright. The last-mentioned havethree chips emitting in the three primary colours (red, green and blue)independently drivable to obtain the complete range of coloursperceptible by human eyes. In this way, the different colours can beused to give specific result indications to the operator.

The converging lens 26, which can be for example a simple plano-convexspherical lens of plastic material, obtained through moulding, is forprojecting the light exiting from the free aperture 25 of diaphragm 24(or, in any case, the figure obtained with the equivalent meansdescribed above) substantially towards the optical code. For thispurpose, it is arranged at such a distance from diaphragm 24 as to focusthe figure on the surface of the optical code at a finite distance,falling within the reading range of the means for acquiring the code ofapparatus 10.

Alternatively, the beam can be collimated, that is, diaphragm 24 can befocused to infinity by lens 26 to limit as much as possible the sizeincrease of the transmitted beam as the distance from lens 26 increases.

The mechanical support 30 is for containing and retaining the aboveelements, namely light source 22, diaphragm 24 and lens 26, or theirequivalents, in fixed position. For this purpose, it is provided withrespective seats, for example slots, not revealed for clarity in FIG. 1.Support 30 is obtained, for example, through moulding, andadvantageously, in the same block comprising the optical acquisitioncamera of the reader. Such a solution allows greater repeatability inthe alignment among the axis of the illumination means, the receptionaxis 14 and axis 28 of the indication projector; moreover, such asolution allows a faster assembling of the pieces. Alternatively,support 30 can be obtained in the shell enclosing apparatus 10.

Each support 30 of the indication means 20 can be arranged in any pointof the reader, provided that the indication light beam is notobstructed. In the embodiment shown in FIG. 1, the projection system isunique, and the relating support 30 is arranged above the opticalreceiving camera of the reader, with axis 28 parallel to the receptionaxis 14 and in symmetrical position with respect to a vertical planepassing through the same reception axis 14. In this way, the centre ofthe luminous figure and that of the illumination figure, typically ascan line, are separated by the same quantity as the distance from theplane of the optical code varies.

Alternatively, the two axes 14, 28, can be inclined with respect to oneanother, and they can intersect at a distance comprised in the readingrange so as to reduce the separation between the indication figure andthe illumination figure in the normal operating conditions.

FIG. 2 illustrates another embodiment of the indication means, as awhole referred to with 40. This indication means is provided with alaser diode 42 as the light source, a collimating objective 46,comprised of one or more lenses, and, possibly, a diffractive element 44or a hologram, arranged downstream of collimator 46, generating thedesired luminous figure on plane P (containing the optical code, ortangent to the surface containing it).

The use of laser 42 as the light source allows having more brilliantluminous figures than those obtainable even with a high-intensity LED.The use of diffractive and/or holographic elements 44 with laser lightallows generating a sharp figure in a greater distance range. In analternative embodiment, the diffractive element or hologram 44 isomitted, and the luminous figure is traced on the code plane by acollimated laser beam, the aiming direction of which is modified instantby instant to draw a bidimensional figure on plane P. Systems of thistype, so-called 2D scan engine lasers, are known.

FIG. 3 shows another embodiment of apparatus for reading optical codesaccording to the invention, wherein the same optics of the illuminationsystem for acquiring the optical code is used, at least partly, for thevisual indication of the reading result.

Apparatus 50 comprises a support 52, properly shaped for housing theelements needed for illumination and reception during the optical codeacquisition. Besides objective 54 and the receiving sensor 56, FIG. 3illustrates the illumination source 58, and slits 60 and lens 62, makingup the illumination optics. More in particular, the illumination source58 shown is comprised of a plurality of LEDs, which typically emit redlight that is shaped into a line by slits 60. According to theinvention, at least one additional or indication LED 64 is provided,arranged next to the illumination LEDs 58. The indication LEDs 64 emitlight which preferably is of a different colour with respect to theillumination LEDs 58, for example green light, so that the generatedindication figure consists in a line similar to the scan line, but of adifferent colour. Alternatively, or in addition, a diaphragm (not shown)or any equivalent element, as described above with reference to FIG. 1,can be arranged in front of the (or each) indication LED 64, so as toobtain a luminous figure having a different shape with respect to thescan line.

This solution allows using the same optics as the illumination systemand thus, besides the LEDs, it does not require the introduction ofadditional components in the reader system. It is worth noting that thelight emitted by the indication LEDs 64 does not interfere with theacquisition of the optical code because, as it shall be describedshortly, the indication LEDs 64 are turned on only when the acquisitionhas occurred, i.e. when sensor 56 is not active anymore.

According to a variation, the indication LEDs can be arranged at thesides of sensor 56, and the optics used for focusing the indicationsources is the reader receiving one (travelled in the oppositedirection). Also in this case, the indication LEDs are turned on onlywhen the acquisition has occurred, that is to say, when sensor 56 is notactive anymore.

In a more advantageous alternative embodiment, the same illuminationsources used for acquiring the optical code are used for indicating thereading result. In this case, different means is used for varying thelight projected onto the optical code, imposing the desired luminousfigure on it.

When said shared illumination source is made up of monochromatic LEDs,which for the code acquisition must illuminate the same code as evenlyas possible, the variation can consist, for example, in intermittentlyturning on and off, through a suitable driving circuit not shown, thevarious LEDs during the indication. Alternatively, the driving circuitcan switch them on, one or more at a time (creating, for example, theeffect of a travelling luminous line) or their intensity can be changed.

Alternatively, the shared light source can be comprised of multi-chipLEDs which, as already described above with reference to FIG. 1, containtwo or more chips, with different emission bands, and which can beturned on independently, such as for example the red and green dual-chipLED LU 5351-JM commercially available from OSRAM, with package having adiameter of 5 mm, emitting at the two wavelengths λ=628 nm (red) andλ=570 nm (green), thanks to two independently drivable chips. In thiscase, only the red chip of each LED is turned on during acquisition,whereas during indication, the red chips are turned off to activate thegreen ones and change the colour of the projected figure.

Again as already described above with reference to FIG. 1, RGB LEDs suchas the LEDs KAA-3528EMBSGC by Kingbright (of the Surface Mount Devicetype) have three chips emitting light in the three primary colours, red(λ=625 nm), green (λ=565 nm) and blue (λ=430 nm), and they can beindependently driven to obtain the entire range of colours perceptibleby human eyes. Thus, in this context it will be possible to use acolour, typically red, for the illumination during the acquisition, anda series of colours for specific result indications to the operator. Forexample, green may be used to indicate that the optical code has beencorrectly decoded; blue to indicate that the optical code cannot be readbecause it falls outside the reading range; yellow to indicate that theoptical code cannot be read because it is damaged; purple to indicatethat the optical code does not fall within a category known by thereader, etcetera.

Laser illumination systems for optical code acquisition can also be usedas light sources for result indication. In fact, laser optical codereaders are typically provided with a mirror system for scanning thelaser beam, which serves for generating an even scan line. The samelaser source can be used for the indication, by stopping the scan systemto obtain a fixed luminous point or by intermittently switching on andoff the laser beam.

The various indication means described can be advantageously associatedto the visual indication on the body of the reading apparatus and/or tothe acoustic indication normally provided for according to the priorart. The flow chart shown in FIG. 4 indicates how the two indicationscan advantageously be managed. In this flow chart, only the case ofindication of a positive reading result is referred to for simplicity,through “LED 1”, which represents the indication on the apparatus body,and “LED 2”, which represents the light source of the indication meansaccording to the various embodiments described above.

At the start up in a step 70, the apparatus enters a standby mode 72,and LED 1 and LED 2 are both off (OFF). In this mode, and as shown byquery 74, the apparatus awaits the start of a reading, for examplesignalled by pressing a button of the apparatus. During acquisition 76,LED 1 and LED 2 are both still off (OFF), whereas the illuminationsource is operating. Once the optical code has been acquired, theapparatus checks, in a step 78, whether it is possible to correctlydecode the optical code. If not, it returns to the stand-by step 74. Incase of positive reading result, in a step 80, this is indicated by theturning on (ON) of both LED 1 and LED 2. At this point, a predeterminedtime T in a step 82 has to elapse, at the end of which LED 2 is turnedoff in a step 84, whereas LED I is kept on while the apparatus awaits,in a step 86, the start of a new reading, to re-enter at the acquisitionstep 76.

The different turning off times of LED 1 and LED 2 are due to the factthat the indication through projection requires a relatively powerfullight source, so it useful to avoid prolonged operation which mightbring to excessive consumptions and to the discharge of possible-batteries. On the contrary, the LED or other light source suitable toemit at the reader body can be kept on, having a lower consumption, asindication of the occurrence of the reading available for the operatorup to the following acquisition.

However, it is evident that delay T is not absolutely necessary, andthat the two LEDs could switch off at the same time.

Still as a matter of mere illustration, the flow chart of FIG. 5illustrates the management of an indication of both a positive resultand a negative result, exemplified by the turning on (ON) and off (OFF)of a LED OK and of a LED NO. Thus, at the start up in a step 90, theapparatus enters in a stand-by mode 92, and LED OK and LED NO are bothoff (OFF). In this mode and as shown by query 94, the apparatus awaitsthe start of a reading, for example signalled by pressing a button ofthe apparatus. During acquisition 96, LED OK and LED NO are still bothoff (OFF), whereas the illumination source is operating. Once theoptical code has been acquired, the apparatus checks, in a step 98,whether it is possible to correctly decode the optical code. In case ofpositive result of the reading, in a step 100, this is indicated byturning on (ON) LED OK. At this point, a predetermined time T1 in a step102 has to elapse, at the end of which LED OK is turned off in a step104, while the apparatus awaits, in a step 106, the start of a newreading, to re-enter at the acquisition step 96. In case of negativeresult of the reading, from the query step 98 the apparatus passes tothe indication of this, in a step 108, turning on (ON) LED NO. At thispoint, a predetermined time T2 in a step 110 has to elapse, at the endof which LED NO is turned off in a step 112, while the apparatus awaits,in step 94, the start of a new reading.

From the previous description, those skilled in the art will understandthat the optical code reading apparatuses described are particularlysuitable to carry out a method for reading optical codes comprising thesteps of:

(a) reading an optical code through an optical code reading device, and

(b) visually indicating the end of the reading step (a) by generating atleast one luminous figure substantially at the optical code.

Advantageously, the above method also comprises the step (c) ofdiscriminating the result of the reading step (a); in this case, theindication step (b) is carried out by generating a predeterminedluminous figure associated to the particular result discriminated instep (c).

In particular, the result discrimination step (c) can be carried out bydiscriminating between positive result and negative result, or bydiscriminating between positive result and at least two differentnegative results.

Preferably, the result indication step (b) is carried out only afterhaving repeated the reading step (a) for a predetermined number of timesreceiving a negative result.

In particular, the predetermined luminous figures generated in thevisual indication step (b) are differentiated by hue, shape and/ordynamics of the luminous intensity.

Advantageously, the visual indication step (b) can be carried out bygenerating also at least one visual signal at the optical code readingapparatus. In this case, the at least one luminous figure generatedsubstantially at the optical code read is turned off before turning offthe visual signal at the optical code reading apparatus.

Advantageously, moreover, all the embodiments of the apparatus or,respectively, of the method according to the invention, can provide thatthe different options which are each time available are selectable bythe user through the management software of the apparatus, both throughthe normal user interface and through programming with predeterminedcodes, for example printed on the reference manual.

It is evident that several modifications, variations, replacements andintegrations can be made to the embodiments described above withoutdeparting from the scope of the invention, as defined by the followingclaims.

What is claimed is:
 1. An apparatus for acquiring and reading opticalcodes, comprising: means for acquiring the optical code, having at leastone acquisition light source, and means for generating an acquisitionlight pattern at the optical code, means for reading the acquiredoptical code, and means for visually indicating the reading resultcomprising: at least one indication light source, distinct from orcoinciding with, the at least one acquisition light source of saidacquisition means, means for imposing an information content indicatingthe reading result to the light emitted by said at least one indicationlight source, and means for projecting the light, having the imposedinformation content, substantially at the optical code, wherein thevisual indication means are arranged so that the light at the opticalcode forms at least one luminous figure having the imposed informationcontent and being different from the acquisition light pattern at leastin one of shape and size.
 2. Apparatus according to claim 1,characterised in that said means for acquiring comprises means forilluminating the optical code, means for detecting the light diffused bythe code and means for transforming said detected diffused light into asignal representing the acquired code, wherein said means for readingthe optical code comprises means for communicating said signalrepresenting the acquired code to a remote processing unit and forreceiving the reading result therefrom.
 3. Apparatus according to claim1, characterised in that said means for imposing the information contentcomprises a switch for turning on and off said at least one indicationlight source.
 4. Apparatus according to claim 1, characterised in thatsaid means for imposing the information content comprises at least oneelement for selectively transmitting the light generated by the at leastone indication light source.
 5. Apparatus according to claim 4,characterised in that said selective transmission element is selectedfrom the group comprised of a diffractive element, a diaphragm having apredetermined shape, a slide, a reflecting surface having apredetermined shape, and a shutter.
 6. Apparatus according to claim 4,characterised in that said selective transmission element is selectedfrom the group comprised of a diffractive element and a hologram. 7.Apparatus according to claim 1, characterised in that said means forimposing the information content comprises a driving circuit of said atleast one light source.
 8. Apparatus according to claim 7, characterisedin that said driving circuit is suitable to drive said at least oneindication light source also in such an operating condition that said atleast one indication light source is said acquisition light sourceduring the acquisition of the optical code.
 9. Apparatus according toclaim 7, characterised in that said at least one indication light sourceis a light source capable of emitting light of at least two chromaticcomponents, and said driving circuit is suitable to drive said at leastone indication light source so as to generate each time light of one ormore of said chromatic components.
 10. Apparatus according to claim 7,characterised in that said driving circuit is suitable to switch on saidat least one indication light source at least intermittently. 11.Apparatus according to claim 7, characterised in that said drivingcircuit is suitable to modulate the intensity of said at least oneindication light source.
 12. Apparatus according to claim 1,characterised in that said means for projecting the light comprises atleast one converging lens for collimating the light and focusing itsubstantially at the optical code.
 13. Apparatus according to claim 1,characterised in that said means for projecting the light is comprisedof the illumination optics of said acquisition means.
 14. Apparatusaccording to claim 1, characterised in that said means for projectingthe light is comprised of the receiving optics of said acquisitionmeans.
 15. Apparatus according to claim 1, characterised in that saidvisual indication means also comprises second means for projecting thelight emitted by said at least one light source towards the operator ofthe apparatus.
 16. Apparatus according to claim 1, characterised in thatsaid visual indication means also comprises second means for projectinga second light emitted by a second indication light source towards theoperator of the apparatus.
 17. Apparatus according to claim 1,characterised in that it further comprises acoustic indication meansassociated to said result indication means.
 18. Apparatus according toclaim 1, characterised in that said means for visually indicating thereading result share at least one element with said means for acquiring.19. Apparatus according to claim 18, characterised in that said at leastone indication light source is distinct from the at least oneacquisition light source, and wherein said at least one shared elementcomprises a common support for said light sources.
 20. Apparatusaccording to claim 1, characterised in that said means for visuallyindicating the reading result comprise a laser scan system. 21.Apparatus according to claim 1, characterised in that said means foracquiring comprise one element selected from the group comprised of aphotodiode, a sensor of the linear type, and a sensor of thebidimensional type.
 22. Method for acquiring and reading optical codescomprising the steps of: (a) acquiring and reading an optical code,wherein said acquiring comprises illuminating the optical code with anacquisition light pattern and (b) visually indicating the result of saidreading step (a) by generating at least one luminous figuresubstantially at the optical code, wherein said at least one luminousfigure differs from the acquisition light pattern at least in one ofshape and size.
 23. Method according to claim 22, characterised in thatsaid indication step (b) is carried out only after having repeated saidreading step (a) for a predetermined number of times receiving anegative result.
 24. Method according to claim 22, characterised in thatsaid indication step (b) is carried out by further generating at least asecond luminous information at an optical code acquiring and readingapparatus performing steps (a) and (b).
 25. Method according to claim24, wherein said luminous information generated substantially at theoptical code is turned off before turning off said second luminousinformation at said optical code reading apparatus.
 26. Method foracquiring and reading optical codes comprising the steps of: (a)acquiring and reading an optical code through an optical code acquiringand reading apparatus, (b) visually indicating the result of saidreading step (a) by generating at least one luminous informationsubstantially at the optical code, and (c) discriminating between atlest three results of said reading step (a), wherein said indicationstep (b) is carried out by generating a predetermined luminousinformation associated to the particular result discriminated in step(c).
 27. Method according to claim 26, characterised in that said resultdiscrimination step (c) is carried out by discriminating among positiveresult and at least two different negative results.
 28. Method accordingto claim 26, characterised in that said predetermined luminousinformation generated in said indication step (b) is differentiated byhue, shape and/or dynamics of the luminous intensity.
 29. An apparatusfor acquiring and reading an optical code, said apparatus comprising: anoptical code reader, having an illuminator of said optical code and areader of said illuminated optical code, wherein said illuminatorgenerates at the optical code an acquisition light pattern; and anindicator of optical code reading status, said indicator including aprojector of visible illumination on an area associated with saidoptical code in response to a result of a reading of said optical codeby said optical code reader, wherein said projector projects lightforming on said area at least one luminous figure which differs fromsaid acquisition light pattern in at least one of shape and size.
 30. Anapparatus according to claim 29, wherein said indicator comprises avisible light projector projecting visible light upon at least a portionof said optical code.
 31. An apparatus according to claim 30, whereinsaid visible light projector includes a light source emitting at leasttwo chromatic components, and, in response to said result, saidprojector emitting one of the at least two chromatic components.
 32. Anapparatus according to claim 30, wherein said projector includes atleast one convergent lens for collimating projected light and focussingsaid light on said optical code.
 33. An apparatus according to claim 29,wherein said indicator comprises an element for selective transmissionof said visible light, said element comprising at least one of adiffractive element, a diaphragm having a predetermined shape, a slide,a reflecting surface having a predetermined shape, a shutter, and ahologram.
 34. An apparatus according to claim 29, wherein said indicatorincludes an acoustic indicator.
 35. A method of acquiring and reading anoptical code, said method comprising the steps of: (a) acquiring andreading an optical code with an optical code reading apparatus, whereinsaid acquiring comprises illuminating the optical code with anacquisition light pattern; and (b) providing, at said optical code, avisible indication of a result of said acquiring and reading step, saidvisible indication being at least one luminous figure different fromsaid acquisition light pattern in at least one of shape and size. 36.The method of claim 35, wherein said acquiring and reading step providesan output indicative of a completed successful reading of said opticalcode, and, in response to said output, said providing step provides avisible indication of said completed successful reading of said opticalcode.
 37. The method of claim 36, wherein said acquiring and readingstep provides an output indicative of a completed unsuccessful readingof said optical code, and, in response to said output, said providingstep provides a visible indication of said completed unsuccessfulreading of said optical code.
 38. The method of claim 37, wherein saidvisible indications of said unsuccessful reading and said successfulreading are different in at least one of hue, shape and luminosity. 39.The method of claim 35, wherein said acquiring and reading step providesan output indicative of a completed unsuccessful reading of said opticalcode, and, in response to said output, said providing step provides avisible indication of said completed unsuccessful reading of saidoptical code.
 40. The method of claim 35, wherein said providing stepcomprises a substep of imposing on said at least one luminous figure aninformation content broader than the mere indication of whether theoptical code has been read or not.
 41. An apparatus for acquiring andreading optical codes, comprising: means for acquiring the optical codethrough illumination of the code with an acquisition light pattern,detection of the light diffused by the code, and its transformation intoan electric signal, having at least one acquisition light source, meansfor reading the acquired optical code through processing of the electricsignal and its interpretation or decoding, and means for visuallyindicating the reading result, characterised in that said visualindication means comprises: at least one indication light source,distinct from or coinciding with, the at least one acquisition lightsource of said acquisition means, means for imposing an informationcontent to the light emitted by said at least one indication lightsource, said information content indicating the result of the readingperformed by said means for reading, and means for projecting the light,having the imposed information content, substantially at the opticalcode, wherein the visual indication means are arranged so that the lightat the optical code forms at least one luminous figure different fromthe acquisition light pattern at least in one of shape and size. 42.Method for acquiring and reading optical codes comprising the steps of:(a) acquiring an optical code through an optical code acquiring andreading apparatus, wherein said acquiring comprises illuminating theoptical code with an acquisition light pattern and generating anelectric signal representative of said optical code, (b) reading theacquired optical code through said optical code acquiring and readingapparatus wherein said reading comprises processing said electric signaland interpreting or decoding it, and (c) visually indicating the resultof said reading step (b), characterized in that said indication step (c)is carried out by generating at least a luminous figure substantially atthe optical code different from the acquisition light pattern in atleast one of shape and size.
 43. An apparatus for acquiring and readingoptical codes, comprising: means for acquiring the optical code, havingat least one acquisition light source, an illumination optics and areceiving optics, means for reading the acquired optical code, and meansfor visually indicating the reading result, said visual indication meanscomprising: at least one indication light source distinct from the atleast one acquisition light source. means for imposing an informationcontent indicating the reading result on the light emitted by said atleast one indication light source, and means for projecting the lightemitted by said at least one indication light source substantially atthe optical code, whereby the light at the optical code forms at leastone figure having the imposed information content, wherein all opticalelements of said means for visually indicating the reading result aredistinct from the illumination optics.
 44. Apparatus according to claim43, characterised in that said means for imposing the informationcontent comprises at least one element for selectively transmitting thelight generated by the at least one indication light source. 45.Apparatus according to claim 44, characterised in that said selectivetransmission element is selected from the group comprised of adiffractive element, a diaphragm having a predetermined shape, a slide,a reflecting surface having a predetermined shape and a shutter. 46.Apparatus according to claim 44, characterised in that said selectivetransmission element is selected from the group comprised of adiffractive element and a hologram.
 47. Apparatus according to claim 43,characterized in that all optical elements of said means for visuallyindicating the reading result are distinct from the receiving optics ofsaid acquisition means.
 48. Apparatus according to claim 43,characterized in that said means for projecting the light is comprisedof the receiving optics of said acquisition means.
 49. Apparatusaccording to claim 43, characterized in that said means for imposing theinformation content comprise a two-dimensional laser scan-engine. 50.Apparatus according to claim 43, characterised in that said means forimposing an information content comprises a driving circuit of said atleast one indication light source.
 51. Apparatus according to claim 43,characterised in that said means for acquiring comprise means forgenerating an acquisition light pattern at the optical code and whereinsaid at least one figure having the imposed information content isdifferent from the acquisition light pattern in at least one of hue,shape and size.
 52. Apparatus according to claim 43, characterised inthat said means for acquiring comprise one element selected from thegroup comprised of a photodiode, a sensor of the linear type, and asensor of the bidimensional type.
 53. Apparatus according to claim 43,characterised in that said visual indication means are contained in asupport for retaining said means in fixed position.
 54. Apparatusaccording to claim 53, characterised in that said means for acquiringthe optical code are contained in a block and said support is obtainedin said block.
 55. An apparatus for acquiring and reading optical codes,comprising: means for acquiring the optical code, through illuminationof the code with an acquisition light pattern, having at least oneacquisition light source, means for reading the acquired optical code,and means for visually indicating the reading result, characterized inthat said visual indication means comprises: at least one indicationlight source, distinct from or coinciding with, the at least oneacquisition light source, means for imposing an information contentindicating the reading result on the light emitted by said at least oneindication light source, and means for projecting the light emitted bysaid at least one indication light source substantially at the opticalcode, whereby the light at the optical code forms at least one luminousfigure having the imposed information content, characterized in thatsaid means for reading the acquired optical code comprises means fordiscriminating between at least two different reading results and inthat said means for visually indicating the reading result are arrangedso that said at least one luminous figure is distinguishable from theacquisition light pattern for each result discriminated by said meansfor discriminating.
 56. Apparatus according to claim 55, characterisedin that said means for imposing the information content comprises atleast one element for selectively transmitting the light generated bythe at least one indication light source.
 57. Apparatus according toclaim 56, characterised in that said selective transmission element isselected from the group comprised of a diffractive element, a diaphragmhaving a predetermined shapes a slide, a reflecting surface having apredetermined shape and a shutter.
 58. Apparatus according to claim 56,characterised in that said selective transmission element is selectedfrom the group comprised of a diffractive element and a hologram. 59.Apparatus according co claim 55, characterised in that said means forimposing the information content comprises a driving circuit of said atleast one light source.
 60. Apparatus according to claim 59,characterised in that said driving circuit is suitable to drive said atleast one indication light source also in such an operating conditionthat said at least one indication light source is said acquisition lightsource during the acquisition of the optical code.
 61. Apparatusaccording to claim 59, characterised in that said at least oneindication light source is a light source capable of emitting light ofat least two chromatic components, and said driving circuit is suitableto drive said at least one indication light source so as to generateeach time light of one or more of said chromatic components. 62.Apparatus according to claim 55, characterised in that said means forimposing the information content comprise a two-dimensional laserscan-engine.
 63. Apparatus according to claim 55, characterised in thatsaid means for visually indicating the reading result share at least oneelement with said acquisition means.
 64. Apparatus according to claim55, characterised in that said means for acquiring the optical codecomprise an illumination optics and a receiving optics and said meansfor visually indicating the reading result share at least one elementwith one of the illumination optics and the receiving optics. 65.Apparatus according to claim 55, characterised in that said at least oneindication light source is distinct from the at least one acquisitionlight source and said means for acquiring the optical code comprise anillumination optics and a receiving optics, and wherein all opticalelements of said means for visually indicating the reading result aredistinct from the illumination optics and the receiving optics. 66.Apparatus according to claim 55, characterised in that said means foracquiring comprise one element selected from the group comprised of aphotodiode, a sensor of the linear type, and a sensor of thebidimensional type.
 67. Method for acquiring and reading optical codes,comprising the steps of: (a) acquiring an optical code, by illuminatingthe optical code with an acquisition light pattern, (b) reading theacquired optical code, and (c) visually indicating the result of saidreading step (b) by generating at least one luminous figuresubstantially at the optical code, characterized by the step (d) ofdiscriminating between at least two different results of said readingstep () and in that in said indication step (c) said at least oneluminous figure is distinguishable form the acquisition light patternfor each result discriminated in said step (d).
 68. Method according toclaim 67, characterised in that said visual indication step (c)comprises the substep of imposing to said at least one luminous figurean information content broader than the mere indication of whether theoptical code has been read or not.
 69. Method according to claim 68,characterised in that said step (d) of discriminating comprisesdiscriminating between different reasons of negative reading result andsaid visual indication step (c) comprises the substep of imposing onsaid at least one luminous figure an information content indicative ofthe reason of negative reading result.
 70. Method according to claim 68,characterised in that said step (d) of discriminating comprisesdiscriminating according to at least part of the content of a positivelyread optical code and said visual indication step (c) comprises thesubstep of imposing on said at least one luminous figure an informationcontent related to said at least part of the content of the positivelyread optical code.
 71. Method according to claim 67, characterised inthat said step (d) of discriminating is carried out by discriminatingbetween a positive result and a negative result.
 72. Method according toclaim 67, characterised in that said step (d) of discriminating iscarried out by disseminating among a positive result and at least twodifferent negative results.
 73. Method according to claim 67,characterised in that said luminous figure generated in said indicationstep (c) is differentiated by hue, shape and/or dynamics of the luminousintensity.